1. Field of the Invention
The present invention relates to dental restoration devices and methods of manufacture thereof. In particular, this invention relates to dental bridges comprising at least one fiber-reinforced structural component and a method of manufacture thereof.
2. Brief Description of the Related Art
In the dental arts, a bridge is a device for the restoration and replacement of one or more natural teeth. It replaces at least one missing tooth and is supported on either side by the remaining teeth. A bridge generally comprises a pontic for replacement of the missing tooth, and connectors which connects the pontic to a retaining member such as a crown formed on an abutment tooth adjacent the pontic. By their nature, bridges must be aesthetic, as well as strong, in order to withstand forces generated by mastication of various types of foods and to maintain the positions of the abutting teeth. Prior art bridges therefore often incorporate a structural reinforcing element to provide strength, and a veneer to provide aesthetics, including ceramic or particulate-filled resin composite veneers.
Not surprisingly, construction of such dental bridge is often a time consuming, involved, and complex process requiring multiple steps. Accordingly, a number of bridge designs are disclosed in the prior art which are intended to either enhance strength or ease of preparation. For example, U.S. Pat. No. 5,074,791 discloses a bridge comprising a preformed pontic, which simplifies preparation. The so-called winged bridge disclosed in U.S. Pat. No. 5,000,687 is designed to enhance bridge strength. U.S. Pat. No. 4,877,400 to Holsclaw discloses a dental bridge comprising a metal pontic rod that is opaqued and installed in refractory model notches. The metal ponltic rod and abutment teeth are coated with a porcelain mix and cured. Since metal is opaque to visible light, metal bridges fail to offer optimum aesthetic qualities. U.S. Pat. No. 4,758,162 to Dobbs discloses a dental bridge comprising a wax occlusal bar and at least one removable wax pontic.
A prefabricated dental bridge in U.S. Pat. No. 4,764,116 to Schoher et al. discloses a prefabricated pontic having a framework that is adjustable by use of a plurality of pliable metal members which interconnect for an open skeleton framework. U.S. Pat. No. 4,457,714 to Klein discloses a prefabricated dental bridge comprising a vertically-orientated pontic element and a pair of horizontally-extending bars disposed on opposite sides of the pontic element.
One problem experienced in prior art bridges featuring particulate-filled resin composite veneers is fracture of the veneer under tensile loading, due to a low strain-to-failure values of the composites. Veneers that are unsupported (due to poor framework design) are also vulnerable to shear under occlusal/incisal loading. Thus, while suitable for their intended purposes, there still remains a need for dental bridges which are aesthetically pleasing, strong and simple for the dentist or dental technician to prepare, and which possess sufficient structural integrity to withstand the stresses associated with mastication.